This invention relates to compositions and methods for sealing pits and fissures in tooth surfaces (i.e. dental enamel).
Almost all children are plagued with dental surface imperfections--commonly termed pits and fissures--which tend to harbor and permit proliferation of microorganisms which can cause formation of caries. Since normal dental hygiene methods such as tooth brushing are relatively ineffective against these physically protected microorganisms it has been the practice of many dentists for a considerable time to attempt to seal the pits and fissures so as to eliminate these sites for microorganism growth.
Commonly used pit and fissure sealants are composed of a polymerizable resin system, such as the polymerizable acrylic system described in U.S. Pat. No. 3,066,112 (Bowen), free of filler. The reason for the common use of a resin system free of filler is indicated by U.S. Pat. No. 3,815,239 (Lee et al.) which teaches that pit and fissure sealants must be of sufficiently low viscosity to be capable of flowing into the pits and fissures to assure complete sealing and good adhesion to the tooth surface.
A common drawback associated with such sealents which are free of filler is that they are transparent (or, at best, translucent) and consequently it is difficult for the dentist to ensure accurate placement and adequate coverage of pits and fissures when using such sealants. The placement difficulty reduces the effectiveness of the treatment itself because the dentist may not observe that some pits and fissures remain unsealed. Further, with respect to some other pits and fissures the dentist may apply much more sealant than necessary simply because of the difficulty in observing the sealant in place. Additionally, periodical re-checks by the dentist to replace worn or dislodged sealant or to apply additional sealant to newly developed pits and fissures are rendered difficult or uncertain because of the difficulty in ascertaining the presence or absence of such transparent or translucent sealings.
Although it might appear possible to provide a suitable discernible pit and fissure sealant by simply adding a pigment to a polymerizable resin, it has been found that the pigment easily settles out of the sealant upon standing. Accordingly, the sealant must either be stirred thoroughly prior to use or the pigment must be added to the resin system and stirred at each time of use.
Others have suggested the incorporation of an ultraviolet fluorescing dye into the polymerizable resin which can then be detected on a tooth surface under ultraviolet light. However, this technique requires the use of ultraviolet light and, furthermore, the dye may leach out of the sealant on the tooth with passage of time.
Similarly, simple dilution of commercially available dental restorative paste by addition of unfilled resin does not produce a desirable pit and fissure sealant because at low levels of dilution the material is too high in viscosity to penetrate adequately into pits and fissures, and at high levels of dilution the material is not sufficiently discernible on tooth surfaces.
The compositions and methods of the present invention are adapted for filling and sealing pits and fissures in tooth surfaces in a discernible manner.